1. Field of the Invention
The present invention relates to an apparatus for and a method of supplying a liquid.
2. Description of the Background Art
A liquid supply apparatus for supplying a liquid through a liquid feed pipe has been hitherto known. A known example of the liquid supply apparatus includes an ink supply apparatus in which ink is supplied from an ink cartridge through a liquid feed tube to a head tank for supplying ink directly to an ink ejection head.
An inkjet recording apparatus including a conventional ink supply apparatus is disclosed, for example, in Japanese Patent Application Laid-Open No. 2011-189701. The inkjet recording apparatus disclosed in Japanese Patent Application Laid-Open No. 2011-189701 includes droplet ejection heads for ejecting ink, head tanks for supplying ink directly to the droplet ejection heads, ink cartridges for adding and supplying ink to the head tanks, and supply tubes for supplying ink from the ink cartridges to the head tanks (in paragraphs 0015 and 0031).
In such an inkjet recording apparatus, the ejection of appropriate amounts of ink droplets from the droplet ejection heads necessitates the adjustment of the pressure of ink in nozzles of the droplet ejection heads to within an appropriate range. The droplet ejection heads, on the other hand, are susceptible to the internal pressure in the head tanks (in paragraph 0003).
In such an ink supply apparatus for supplying ink from the ink cartridges to the head tanks, an abrupt change in ink supply volume causes an abrupt change in internal pressure in the head tanks. As a result, appropriate amounts of ink droplets cannot be ejected from the droplet ejection heads.
In particular, there are cases where a high-power pump is used for supply of ink in a large-scale inkjet printing machine which consumes a large amount of ink. Thus, large vibrations occur in some cases when the pump is turned on or off or when the output of the pump is changed. This results in apprehension that an abrupt change in internal pressure in the droplet ejection heads or the head tanks occurs to influence printing quality.